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x.umn radiology > Biological Effects of Ionizing Radiation (V. 1) > Flashcards

Biological Effects of Ionizing Radiation (V. 1) Flashcards

(77 cards)

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1
Q

dose to air, as radiation comes out of x-ray tube

A

exposure, air kerma

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2
Q

dose to tissues, as radiation enters body of patient

A

absorbed dose, equivalent dose, effective dose

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3
Q

a measure of the ionization produced in the air by x-rays or gamma rays

A

exposure

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4
Q

traditional unit of exposure; SI unit

A

roentgen (R); air kerma (Gy or Gray)

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5
Q

what does “kerma” stand for?

A

kinetic energy released in matter

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6
Q

air kerma measures _______ transferred from ____ to _____ of the absorber

A

kinetic energy, photons, electrons

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7
Q

kerma values in the is called….

A

air kerma

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8
Q

absorbed dose is energy transferred from ionizing radiation per ________ of _____

A

unit mass, irradiated material

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9
Q

traditional unit of absorbed dose; SI unit

A

rad (radiation absorbed dose); Gray (Gy)

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10
Q

absorbed dose varies with __________ and __________

A

type/energy of radiation, type of absorbing material

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11
Q

equivalent dose is used to compare the ______ of different types of radiation on a _______

A

biologic effects, tissue/organ

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12
Q

equivalent dose depends on ____

A

LET

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13
Q

high LET radiation causes (more/less) harm than low LET radiation

A

more

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14
Q

tradition unit for equivalent dose; SI unit

A

rem (roentgen equivalent man); Sievert (Sv)

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15
Q

1 Sv = __ Gy

A

1 Gy

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16
Q

effective dose is used to estimate risk of ______

A

radiation in humans

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17
Q

true/false? not all tissues respond identically to radiation

A

true

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18
Q

effective dose is the ________ of the _________ of a tissue and ________ applicable to each of the tissue irradiated

A

sum of the products, equivalent dose, weighting factors

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19
Q

unit of effective dose

A

Sv

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20
Q

a measurement of decay or disintegration of a sample radioactive material

A

radioactivity

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21
Q

traditional unit of radioactivity; SI unit

A

Curie (Ci), Becquerel (Bq)

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22
Q

a badge special film that is particularly sensitive to x-rays

A

film badge

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23
Q

_______ on exposed and processed film is related to exposure received by operator

A

optical density

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24
Q

what does TLD stand for?

A

thermoluminscence dosimeter

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25
when TLD is exposed, it absorbs energy and stores it as _______
excited electrons
26
_______ of TLD provides the dose received by operator
intensity of light
27
OSL is stimulated with ____
LED
28
radiation produces ionizations/excitations of essential molecules, such as...
DNA, enzymes, ATP, etc.
29
damage to ____ is much worse than damage to _____
DNA, cell membrane
30
effect in which damage/mutation occurs at the site where radiation is deposited
direct effect
31
effect in which radiation initially acts on water molecules to cause ionization
indirect effect
32
____ direct effects; __ indirect effects
1/3; 2/3
33
direct effects of radiation characteristics...
- generates free radicals - free radicals either dissociate or cross link - altered biological molecules differ from original molecules (structure/function)
34
indirect effects of radiation characteristics...
- body is 70% water - high likelihood that x-ray photons will interact with water in body - radiolysis of water
35
indirect effects of radiation produces (from radiolysis of water)
hydroperoxyl, hydrogen peroxide (both are oxidizing agents and toxins)
36
do you need to know the direct/indirect effect equations on the PPT?
no, you don't. don't stress! :)
37
radiation effects types (2); which is more damaging?
short term, long term: long term more damaging
38
types of long term effects
cancer, genetic mutation, mental/physical retardation of children
39
cancer may occur ____ years later from exposure
10-30
40
histologically, radiation induced cancers are _______ than other cancers
not different
41
probability of cancer/genetic mutation increases with ________, but severity does not depend on ________
increasing the dose, the amount of the dose
42
random; having a random probability distribution that may not be predicted precisely; unpredictable
stochastic
43
a somatic effect that increases in severity with increasing absorbed dose
deterministic effects
44
examples of deterministic effects
cataract, skin erythema, fibrosis, abnormal growth
45
deterministic effects are not by ____ but are a _____
chance, "will-happen" event
46
deterministic effects usually (are/are not) from diagnostic radiology
are not
47
if radiation damage to DNA is severe enough, __________ may be detected, but DNA molecules can be damaged ______
visible chromosomes aberration; without chromosome aberration
48
effect of radiation on individual gene
point mutation
49
result of point mutation
- loss of gene/set of gene - mutation in gene/set of genes ...and the cell may exhibit abnormal function
50
several kinds of alterations in the chromosomes have been described
chromosome alteration
51
effect of chromosome alterations
- breaking of one or more chromosome | - broken ends seem to possess ability to join together again after separation
52
in chromosome aberration... if damage is after DNA synthesis, then _____ if damage is before DNA synthesis, then ____
``` after = only one arm of chromosome is broken before = both arms of chromosome are broken ```
53
chromosome repair without errors
restitution
54
chromosome "repair"/error with loss
deletion (losing part of structure)
55
if there is more than one break in chromosome, _____ may occur
broken fragments joining in different combinations
56
illegitimate union characteristics...
- defectively repaired chromosome - pre-replication - 1 break in each chromosome - causes U-shaped and extra
57
ring formation, acentric fragment characteristics...
- defectively repaired chromosome - pre-replication - breaks in each arm of the same chromosome
58
translocation characteristics...
- defectively repaired chromosome - 2 different pre-replication - 1 break in each chromosome - "swapped" appearance
59
a large proportion of damage will result in mis-repair which can result in the formation of _______ that cause _____
gene/chromosomal mutations, malignant development (cancer)
60
ionizing radiation also affect cell division, resulting in _____, and thus _____. This is the basis of ____
arrested mitosis, retardation of growth, radiotherapy of neoplasms
61
cells are more sensitive to radiation during the _____________
last part of resting phase, early part of prophase
62
to stop cancer cells from repairing themselves (in radiotherapy), you must give ________
fractionated dose (multiple doses/not all at once)
63
Bergonie/Tribondeu key statement: "cells are sensitive to radiation ____________ and in _____________"
in proportion to their proliferative activity, inverse proportion to their degree of differentiation
64
rapidly dividing are ____ than more differentiated, slowly dividing cells
more sensitive
65
____ are radiosensitive, ____ are radioresistant
stem cells, mature cells
66
younger tissues/organs are _____
radiosensitive
67
tissues with high metabolic rate are ____
radiosensitive
68
high proliferation/high growth rate are ______
radiosensitive
69
notable Bergonie/Tribondeu
lymphocyte
70
lymphocyte is...
- not capable of proliferative activity - is a differentiated cell - one of the most radiosensitive cells in body
71
highly radiosensitive
- lymphoid organs - bone marrow - testes - intestine - mucous membrane
72
intermediate radiosensitive
- fine vasculature - growing cartilage - growing bone - salivary glands - lungs - kidney liver
73
low radiosensitive
- optic lens - mature erythrocytes - muscle cells - neurons
74
cell death for differentiated (nerve, muscle, secretory, etc.) cells = _____
loss of function
75
cell death for proliferating cells (stem cells, intestinal cell) =
loss of capacity for proliferation (also known as reproductive death)
76
densely ionizing = | sparsely ionizing =
``` densely = neutrons, alpha rays sparsely = x-rays ```
77
cytoplasmic changes play a _____ in arrested mitosis and cell death
minor role

x.umn radiology (15 decks)

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